Pusher blades are the conventional mechanisms for moving slide-type test elements in an analyzer from one location to another. For example, such blades have been used to push a test element out of one or two stacks of elements, into another part of an analyzer so that the test element can be further processed to detect an analyte in a body liquid deposited on the test element. An example is pusher blade 60 in FIG. 4 of U.S. Pat. No. 4,512,952.
As such analyzers become more and more involved in their processing of the test elements, the blades must traverse greater and greater distances. For example, in the aforementioned patent, the blade must traverse not only one stack of elements to push an element out of such stack, but in addition, it must traverse a second adjacent stack that is an alternate supply of elements. The conventional construction for the blade in all such instances is a rigid one. This is due to the use of a ridge that provides a rack for a rack-and-pinion drive of the blade, as is explained hereinafter. Thus, the problem becomes one of providing sufficient, usually horizontal, space for a longer rigid blade to operate in. This in turn makes the analyzer longer or wider, just to accommodate such a long, rigid pusher blade.
Therefore, prior to this invention there has been a need for a pusher blade construction which will provide the longer traversals now being required of such blades, without unduly extending the dimensions of the analyzer just to accommodate a long, rigid blade.